Fixing apparatus and evaporation method

ABSTRACT

The present disclosure discloses a fixing apparatus for fixing a substrate to be processed below a bearing base during an evaporation process, the substrate to be processed includes a base substrate, a ferromagnetic material is formed on a front surface or a back surface of the base substrate, and a magnetic field generator is disposed on a back surface of the bearing base at a location corresponding to the ferromagnetic material; the magnetic field generator is configured to generate a magnetic field so that the ferromagnetic material and the magnetic field generator are approaching to each other under an effect of the magnetic field generated by the magnetic field generator to fix a front surface of the bearing base with the back surface of the base substrate. An evaporation method is further disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a divisional application of U.S. patentapplication Ser. No. 15/517,796 filed Apr. 7, 2017, which was theNational Stage of International Application No. PCT/CN2016/074098 filedFeb. 19, 2016 which claims priority from Chinese Patent Application No.201510561608.6 filed on Sep. 6, 2015, the entire contents of each whichare incorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates to the field of display technology,particularly to a fixing apparatus and an evaporation method.

BACKGROUND

In the manufacturing field of Organic Light-Emitting Diode (hereinafterreferred to as OLED) products, an evaporation method is used as one ofthe relatively matured ways.

During a manufacturing process of OLED products by using the evaporationmethod, it requires to fix a substrate to be processed below a bearingbase. More specifically, the substrate to be processed may include abase substrate having a front surface on which display elements(including OLED, thin film transistor (TFT) and the like) are formed.For fixing the substrate, a back surface of the base substrate is fixedwith a front surface of the bearing base through a double sided tape.When the substrate to be processed is fixed with the bearing base, ametallic mask plate is further disposed at a side of the substrate to beprocessed far away from the bearing base, then an electroluminescencematerial can be evaporated onto the front surface of the base substrate.

However, during practical evaporation processes, an adhesive force ofthe double sided tape would be reduced with time, which results in aseparation of the substrate to be processed from the bearing base, andhence problems such as falling or crack of the substrate to beprocessed. At the same time, the double sided tape, as a consumable,need to be replaced by new ones frequently, which goes againstcontinuous production.

SUMMARY

Embodiments of the present disclosure provide a fixing apparatus and anevaporation method, which can effectively fix a substrate to beprocessed with a bearing base during an evaporation process.

In order to achieve the above-mentioned objectives, embodiments of thepresent disclosure provide a fixing apparatus for fixing a substrate tobe processed below a bearing base during an evaporation process. Thesubstrate to be processed includes a base substrate having a frontsurface on which display elements are to be formed; a ferromagneticmaterial is formed on the front surface or a back surface of the basesubstrate; and a magnetic field generator is disposed on a back surfaceof the bearing base at a location corresponding to the ferromagneticmaterial.

The magnetic field generator is configured to generate a magnetic fieldso that the ferromagnetic material and the magnetic field generator areapproaching to each other under an effect of the magnetic field to fix afront surface of the bearing base with the back surface of the basesubstrate.

Optionally, the ferromagnetic material is formed on the back surface ofthe base substrate and constitutes multiple ferromagnetic patternslocated at pixel regions of the substrate to be processed.

The magnetic field generator includes multiple first magnetic structureseach corresponding to at least one of the ferromagnetic patterns.

Optionally, a thickness of each of the ferromagnetic patterns is largerthan or equal to 5 nm.

Optionally, each of the ferromagnetic patterns has a rectangle shape.

Optionally, the ferromagnetic patterns are disposed in one-to-onecorrespondence with the pixel regions, and each of the ferromagneticpatterns is located at a center of a corresponding pixel region.

Optionally, all the ferromagnetic patterns are electrically connected.

Optionally, the substrate to be processed further includes a flexiblesubstrate disposed between the display elements and the base substrate.The flexible substrate is mixed with the ferromagnetic material in apowder form.

The magnetic field generator includes multiple first magnetic structurescorresponding to the pixel regions of the substrate to be processed.

Optionally, a material of the flexible substrate is polyimide,polycarbonate or polyether sulfone.

Optionally, the substrate to be processed further includes a flexiblesubstrate disposed between the display elements and the base substrate.

The ferromagnetic material is located at a side of the flexiblesubstrate far away from the base substrate, and constitutes multipleferromagnetic patterns located at the pixel regions of the substrate tobe processed.

The magnetic field includes multiple first magnetic structures eachcorresponding to at least one of the ferromagnetic patterns.

Optionally, a material of the flexible substrate is polyimide,polycarbonate or polyether sulfone.

Optionally, a thickness of each of the ferromagnetic patterns is rangedfrom 5 nm to 1 mm.

Optionally, the back surface of the bearing base is provided withmultiple second magnetic structures corresponding to non-pixel regionsof the substrate to be processed.

The fixing apparatus further includes: each of the second magneticstructures is configured to generate a magnetic field so that a maskplate used during the evaporation process and the magnetic fieldgenerator are approaching to each other under an effect of the magneticfield generated by the second magnetic structure.

Optionally, the display elements include a thin film transistor (TFT)and an insulating layer which is formed on a side of the TFT far awayform the base substrate; the ferromagnetic material is formed on a sideof the insulating layer far away from the base substrate.

The ferromagnetic material constitutes multiple ferromagnetic patternslocated at non-pixel regions of the substrate to be processed.

The magnetic field generator includes multiple first magnetic structureseach corresponding to at least one of the ferromagnetic patterns.

Optionally, a thickness of each of the ferromagnetic patterns is largerthan or equal to 5 nm.

Optionally, a width of each of the ferromagnetic patterns is smallerthan a linear width of a mask plate used in the evaporation process.

Optionally, the ferromagnetic material is at least one selected from agroup consisted of Fe, Co and Ni.

Optionally, the magnetic field generator is an electromagnet.

In order to achieve the above-mentioned objectives, embodiments of thepresent disclosure further provide an evaporation method, includingfixing a front surface of a bearing base with a back surface of a basesubstrate by utilizing the above-mentioned fixing apparatus.

The advantageous effects of the preset disclosure lie in that:embodiments of the present disclosure provide a fixing apparatus and anevaporation method, in which the fixing apparatus is configured to fix asubstrate to be processed with a bearing base during an evaporationprocess. The substrate to be processed includes a base substrate havinga front surface on which display elements are to be formed. Aferromagnetic material is formed on the front surface or a back surfaceof the base substrate. A magnetic field generator is disposed at alocation on a back surface of the bearing base corresponding to theferromagnetic material. The fixing apparatus includes a magnetic fieldgenerator configured to generate a magnetic field so that theferromagnetic material and the magnetic field generator are approachingto each other under an effect of the magnetic field to fix a frontsurface of the bearing base with the back surface of the base substrate.In the present disclosure, by generating a magnetic field through themagnetic field generator, the magnetic field generator and theferromagnetic material are approaching to each other so that thesubstrate to be processed is fixed below the bearing base. In this way,problems such as falling and crack of the substrate to be processedduring the evaporation process can be effectively avoided because theadhesive force between the magnetic field generator and theferromagnetic material will not be reduced with processing time.

BRIEF DESCRIPTION OF THE DRAWINGS

Hereafter, the embodiments of the present invention will be described ina more detailed way with reference to the accompanying drawings, so asmake one person skilled in the art be able to understand the presentinvention more clearly, wherein:

FIG. 1 is a flow chart illustrating an operation of a fixing apparatusprovided by a first embodiment of the present disclosure;

FIG. 2 is a schematic diagram illustrating a first solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure;

FIG. 3 is a schematic diagram illustrating the substrate to be processedin FIG. 2;

FIG. 4 is a schematic diagram illustrating a second solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure;

FIG. 5 is a schematic diagram illustrating a third solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure;

FIG. 6 is a schematic diagram illustrating a fourth solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure;

FIG. 7 is a schematic diagram illustrating relationships among a firstmagnetic structure, a ferromagnetic pattern and a mask plate in FIG. 6.

DETAILED DESCRIPTION

Hereafter, the technical solutions in the embodiments of the presentdisclosure will be described in a clearly and fully understandable wayin connection with the drawings in the embodiments of the presentdisclosure. It is obvious that the described embodiments are just a partbut not all of the embodiments of the disclosure. Based on the describedembodiments herein, one person skilled in the art can obtain otherembodiment(s), without any inventive work, which should be within thescope of the disclosure.

Unless otherwise defined, the technical terminology or scientificterminology used herein should have the same meaning as commonlyunderstood by one of ordinary skill in the art to which this inventionbelongs. Likewise, terms like “first,” “second,” etc., which are used inthe description and the claims of the present application for invention,are not intended to indicate any sequence, amount or importance, butdistinguish various components. The phrases “connect”, “connected”,etc., are not intended to define a physical connection or mechanicalconnection, but may include an electrical connection, directly orindirectly. “On,” “under,” “left,” “right” or the like is only used todescribe a relative positional relationship, and when the absoluteposition of a described object is changed, the relative positionalrelationship might also be changed accordingly.

The First Embodiment

FIG. 1 is a flow chart illustrating an operation of a fixing apparatusprovided by a first embodiment of the present disclosure. As illustratedin FIG. 1, the fixing apparatus is used for fixing a substrate to beprocessed below a bearing base during an evaporation process. Thesubstrate to be processed includes a base substrate 1 having a frontsurface on which display elements (not illustrated) are to be formed; aferromagnetic material is formed on the front surface or a back surfaceof the base substrate 1; and a magnetic field generator is disposed on aback surface of the bearing base 2 at a location corresponding to theferromagnetic material.

The operation of the fixing apparatus includes step S101, generating amagnetic field by the magnetic field generator so that the ferromagneticmaterial and the magnetic field generator are approaching to each otherunder an effect of the magnetic field generated by the magnetic fieldgenerator to fix a front surface of the bearing base with the backsurface of the base substrate 1.

In the present embodiment, by pre-disposing a ferromagnetic material onthe front or back surface of the base substrate 1 and then disposing amagnetic field generator on the back surface of the bearing base 2 at alocation corresponding to the ferromagnetic material, a magnetic fieldis generated by the magnetic field generator to allow the ferromagneticmaterial and the magnetic field generator being approaching to eachother, thereby fixing the substrate to be processed below the bearingbase 2. In this way, problems such as falling and crack of the substrateto be processed during the evaporation process can be effectivelyavoided because the adhesive force between the magnetic field generatorand the ferromagnetic material will not be reduced with processing time.

It should be explained that, as used herein, the terms “front surface”and “back surface” refer to two surfaces which are opposite to eachother. With reference to the drawings, the “front surface” refers to alower surface of an object as discussed while the “back surface” refersto an upper surface of the object as discussed.

Hereinafter several ways of fixing the substrate to be processed withthe bearing base 2 in the present embodiment are discussed in moredetails in conjunction with the drawings.

FIG. 2 is a schematic diagram illustrating a first solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure, and FIG. 3 is a schematic diagramillustrating the substrate to be processed in FIG. 2. As illustrated inFIG. 2 and FIG. 3, the ferromagnetic material is located at the backsurface of the base substrate 1, and constitutes multiple ferromagneticpatterns 4 which are located in pixel regions of the substrate to beprocessed. The magnetic field generator includes multiple first magneticstructures 3 each corresponding to at least one of the ferromagneticpatterns 4.

In FIG. 2, by utilizing a magnetic attraction force between the firstmagnetic structure 3 and the corresponding ferromagnetic pattern 4, theferromagnetic pattern 4 is contacted with the front surface of thebearing base 2 and fixed there, so as to achieve the objective of fixingthe base substrate 1 right below the bearing base 2. At the same time,in order to ensure that the magnetic attraction force between the firstmagnetic structure 3 and the corresponding ferromagnetic pattern 4 issufficient to fix the ferromagnetic pattern 4 with the bearing base 2, athickness of the ferromagnetic pattern 4 is larger than or equal to 5nm, optionally.

It should be explained that the base substrate 1 in the presentembodiment can be a glass substrate.

Optionally, the magnetic field generator is consisted of anelectromagnet. That is, each of the first magnetic structures 3 can be asingle electromagnet, so that the magnetic attraction force between theelectromagnet and the corresponding ferromagnetic pattern 4 iscontrollable by controlling a magnetic field intensity of theelectromagnet.

During practical evaporation process, a middle portion of the substrateto be processed may be concaved due to its own gravity. In such case,the number of the electromagnet disposed corresponding to the middleportion of the substrate to be processed can be increased so as toenhance the magnetic attraction force between the electromagnet and theferromagnetic pattern 4 located at the middle portion of the substrateto be processed; in this way, the problem that the middle portion of thesubstrate to be processed may be concaved is effectively solved. Ofcourse, those skilled in the art would be appreciated that the magneticfield intensity of the electromagnet is controllable according topractical conditions during the evaporation process of the substrate tobe processed, in order to ensure that the substrate to be processed isalways in a flat state.

In the present embodiment, optionally, each of the ferromagneticpatterns 4 has a rectangular shape, and the ferromagnetic patterns 4 aredisposed in one-to-one correspondence with the pixel regions of thesubstrate; for example, each of the ferromagnetic patterns is disposedat a center of a corresponding pixel region. It should be explainedthat, in the present embodiment, the ferromagnetic patterns 4 can beformed in a single process by using methods such as sputtering andelectronic beam evaporation, or can be formed by using processes such asfilm forming, exposing, etching and developing.

Optionally, all the ferromagnetic patterns 4 are electrically connectedthrough metallic leads 7. In such case, circuits are constituted amongthe ferromagnetic patterns 4 to effectively eliminate static electricityattached on the substrate to be processed.

It should be explained that, for the case illustrated in FIG. 2, athickness of the ferromagnetic pattern 4 may be larger than or equal to5 nm, in order to ensure that the magnetic attraction force between themagnetic field generator and each of the ferromagnetic patterns 4 issufficient to fix the substrate to be processed below the bearing base2. Furthermore, the ferromagnetic pattern 4 remained on the back surfaceof the base substrate 1 upon finishing the evaporation process can beremoved by using etching process, in order to prevent the ferromagneticpattern 4 from affecting the brightness of the display device asproduced.

Additionally, what is similar with the substrate to be processed isthat, a mask plate 6 used during the evaporation process may be deformedcorrespondingly due to influence factors such as its own gravity andtemperature. In order to solve such technical problem, in the presentembodiment, the back surface of the bearing base 2 is provided withmultiple second magnetic structures 5 at locations corresponding tonon-pixel regions of the substrate to be processed. The second magneticstructures 5 are configured to generate an action force with the maskplate 6 used during the evaporation process. By controlling the magneticfield intensity generated by the second magnetic structures 5respectively, the deformation of the mask plate 6 can be effectivelyrestrained.

In the present embodiment, besides the step S101, the operation of thefixing apparatus further includes Step 102: generating a magnetic fieldby the second magnetic structure 5 so that a mask plate used during theevaporation process is approaching to a corresponding second magneticstructure 5 under an effect of the magnetic field generated by thesecond magnetic structure 5.

It should be explained that, the first magnetic structure 3 and thesecond magnetic structure 5 will not interference with each otherbecause the first magnetic structure 3 is located in the pixel regionwhile the second magnetic structure 5 is located in the non-pixelregion.

FIG. 4 is a schematic diagram illustrating a second solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure. As illustrated in FIG. 4, what isdifferent from FIG. 2 is that the substrate to be processed furtherincludes a flexible substrate applicable in a flexible display device.For example, a flexible substrate 9 can be disposed between the displayelements and the base substrate 1. The flexible substrate 9 is mixedwith powder ferromagnetic material. The magnetic field generatorincludes multiple first magnetic structures 3 corresponding to the pixelregions of the substrate to be processed. A material of the flexiblesubstrate can be polyimide, polycarbonate or polyether sulfone.

It should be explained that, a sacrificial layer 8 can be furtherdisposed between the base substrate 1 and the flexible substrate 9. Uponfinishing the process of the substrate, the sacrificial layer 8 can beremoved by using specific methods to separate the flexible substrate 9from the base substrate 1.

In FIG. 4, a magnetic attraction force is generated between each of thefirst magnetic structures 3 and the flexible substrate 9 mixed withpowder ferromagnetic material, so that the back surface of the basesubstrate 1 is contacted with the front surface of the bearing base 2and fixed there, so as to achieve the objective of fixing the basesubstrate 1 right below the bearing base 2. Of course, each of the firstmagnetic structures 3 in FIG. 4 can be a single electromagnet, and itcan ensure that the substrate to be processed is always in a flat stateby respectively controlling the magnetic field intensity generated bythe electromagnets.

It should be explained that, for the case illustrated in FIG. 4, atransmittance of the flexible substrate 9 would not be significantlyinfluenced because the powder ferromagnetic material is mixed inpolyimide, polycarbonate or polyether sulfone.

Of course, in the technical solution of FIG. 4, the back surface of thebearing base 2 can be provided with second magnetic structures 5 asillustrated in FIG. 2, at locations corresponding to the non-pixelregions, so as to restrain the deformation of the mask plate 6 usedduring the evaporation process, the particular principle of which isdiscussed in the preceding paragraphs and will not be repeated herein.

FIG. 5 is a schematic diagram illustrating a third solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure. As illustrated in FIG. 5, aflexible substrate 9 is disposed between the display elements and thebase substrate 1, and a material of the flexible substrate 9 can bepolyimide, polycarbonate or polyether sulfone. The ferromagneticmaterial is located at a side of the flexible substrate 9 far away fromthe base substrate 1 (an insulating layer is disposed between theferromagnetic material and the display device), and constitutes multipleferromagnetic patterns 4 which are located at the pixel regions of thesubstrate to be processed. The magnetic field generator includesmultiple first magnetic structures 3 each corresponding to at least oneof the ferromagnetic patterns 4.

In FIG. 5, by utilizing a magnetic attraction force between the firstmagnetic structure 3 and the corresponding ferromagnetic pattern 4, theferromagnetic pattern 4 is contacted with the front surface of thebearing base 2 and fixed there, so as to achieve the objective of fixingthe base substrate 1 below the bearing base 2. Of course, each of thefirst magnetic structures 3 in FIG. 5 can be a single electromagnet, andit can ensure that the substrate to be processed is always in a flatstate by respectively controlling the magnetic field intensity generatedby the electromagnets.

It should be explained that, in FIG. 5, the ferromagnetic pattern 4cannot be removed by an etching process and hence may reduce anillumination intensity of the display device as produced. Thus, in orderto ease the influence of the ferromagnetic pattern 4 to the illuminationintensity of the display device as produced, the ferromagnetic pattern 4may be designed with a smaller film thickness. However, an excessivelythin film may result in a reduced magnetic attraction force between thefirst magnetic structure 3 and the ferromagnetic pattern 4, which maylead to failure of fixing the substrate to be processed below thebearing base 2. In view of the above, for the case illustrated in FIG.5, a thickness of the ferromagnetic pattern 4 is ranged from 5 nm to 1mm.

Of course, in the technical solution of FIG. 5, the back surface of thebearing base 2 can be provided with second magnetic structures 5 asillustrated in FIG. 2, at locations corresponding to the non-pixelregions, so as to restrain the deformation of the mask plate 6 usedduring the evaporation process, the particular principle of which isdiscussed in the preceding paragraphs and will not be repeated herein.

It should be explained that, a sacrificial layer 8 can be furtherdisposed between the base substrate 1 and the flexible substrate 9. Uponfinishing the process of the substrate, the sacrificial layer 8 can beremoved by using specific methods to separate the flexible substrate 9from the base substrate 1.

FIG. 6 is a schematic diagram illustrating a fourth solution of fixing asubstrate to be processed with a bearing base according to the firstembodiment of the present disclosure, and FIG. 7 is a schematic diagramillustrating relationships among a first magnetic structure, aferromagnetic pattern and a mask plate in FIG. 6. As illustrated in FIG.6 and FIG. 7, the display elements include a TFT 10 and an insulatinglayer 11 which is formed on a side of the TFT 10 far away from the basesubstrate 1. The ferromagnetic material is located at a side of theinsulating layer 11 far away from the base substrate 1, and constitutesmultiple ferromagnetic patterns 4 which are located at the non-pixelregions of the substrate to be processed. The magnetic field generatorincludes multiple first magnetic structures 3 each corresponding to atleast one of the ferromagnetic patterns 4.

In FIG. 6, in order to ensure that the magnetic attraction force betweenthe first magnetic structure 3 and the corresponding ferromagneticpattern 4 is sufficient to fix the ferromagnetic pattern 4 with thebearing base 2, a thickness of the ferromagnetic pattern 4 is largerthan or equal to 5 nm, optionally.

What is different from the technical solutions of FIG. 4 and FIG. 5 isthat, the ferromagnetic patterns 4 in FIG. 6 are only located at thenon-pixel regions of the substrate to be processed.

In the technical solution illustrated in FIG. 6, a width of theferromagnetic pattern 4 is smaller than a linear width of the mask plate6 used during the evaporation process. At the same time, a size of thefirst magnetic structure 3 can be made relatively larger. As illustratedin FIG. 7, by way of example, an orthographic projection of theferromagnetic pattern 4 on the mask plate 6 covers an area A on the maskplate 6, but doesn't cover an area B on the mask plate 6. In this way,the first magnetic structure 3 can not only generate an action force F1with the ferromagnetic pattern 4 but also generate an action force F2with the area B on the mask plate 6. Therefore, in the technicalsolution illustrated in FIG. 6, the substrate to be processed can befixed and the deformation of the mask plate 6 used during theevaporation process can be controlled merely by using the first magneticstructure 3.

It should be explained that, in the technical solution illustrated inFIG. 6, it's also possible to fix the substrate to be processed by usingthe first magnetic structure 3 and to control the deformation of themask plate 6 by using the second magnetic structure 5, similarly withthat of the first, second and third solutions. In such case, the firstmagnetic structure 3 is disposed corresponding to the area A, while thesecond magnetic structure 5 is disposed corresponding to the area B.

In addition, the magnetic field generator illustrated in FIG. 6 can alsobe an electromagnet.

Those skilled in the art would be appreciated that, all the solutions inwhich a bearing base 2 is fixed with a base substrate 1 by utilizing amagnetic field effect between a ferromagnetic material and a magneticfield generator through disposing the magnetic field generator on thebearing base 2 while disposing the ferromagnetic material on a frontsurface or back surface of the base substrate 1 should be considered asfallen within the scope of the present disclosure. Moreover, theforegoing four technical solutions are merely described by way ofexample without limiting the embodiments of the present disclosurethereto. Other possible technical solutions of the present disclosureare conceivable to those skilled in the art and will not be enumeratedhere.

In the present embodiment, the ferromagnetic material can be at leastone selected from a group consisted of Fe, Co and Ni.

The Second Embodiment

The second embodiment of the present disclosure further provides anevaporation method, including: fixing a base substrate below a bearingbase by using the fixing apparatus according to the first embodiment;and performing an evaporation process to the substrate to be processed.Regarding the step of fixing a base substrate below a bearing base,reference can be made to the corresponding contents in the foregoingfirst embodiment without repeating here.

Embodiments of the present disclosure provide a fixing apparatus and anevaporation method. During fixing a base substrate below a bearing base,by pre-disposing a ferromagnetic material on the front or back surfaceof the base substrate and then disposing a magnetic field generator onthe back surface of the bearing base at a location corresponding to theferromagnetic material, a magnetic field is generated by the magneticfield generator to allow the ferromagnetic material and the magneticfield generator being approaching to each other, thereby fixing thesubstrate to be processed below the bearing base. In this way, problemssuch as falling and crack of the substrate to be processed during theevaporation process can be effectively avoided because the adhesiveforce between the magnetic field generator and the ferromagneticmaterial will not be reduced with processing time.

The foregoing embodiments merely are exemplary embodiments of thedisclosure and not intended to define the scope of the disclosure, andany variations or replacements which can be easily thought of by thoseskilled in the art in the technical scope of the disclosure shall fallwithin the scope of disclosure. Therefore, the scope of the disclosureshall be determined by the scope of the appended claims.

The present disclosure claims the benefits of Chinese patent applicationNo. 201510561608.6, which was filed with the SIPO on Sep. 6, 2015 underthe title of “FIXING APPARATUS AND EVAPORATION METHOD” and is fullyincorporated herein by reference as part of this application.

The invention claimed is:
 1. A fixing apparatus for fixing a substrateto be processed below a bearing base during an evaporation process, thesubstrate to be processed comprising a base substrate having a frontsurface on which display elements are to be formed, the fixing apparatuscomprising: a ferromagnetic material being formed on the front surfaceor a back surface of the base substrate; and a magnetic field generatorbeing disposed on a back surface of the bearing base at a locationcorresponding to the ferromagnetic material; the magnetic fieldgenerator being configured to generate a magnetic field so that theferromagnetic material and the magnetic field generator beingapproaching to each other under an effect of the magnetic fieldgenerated by the magnetic field generator to fix a front surface of thebearing base with the back surface of the base substrate; theferromagnetic material is located on the back surface of the basesubstrate, and constitutes multiple ferromagnetic patterns which arelocated in pixel regions of the substrate to be processed, and themagnetic field generator comprises multiple first magnetic structureseach corresponding to at least one of the ferromagnetic patterns; theback surface of the bearing base is provided with multiple secondmagnetic structures corresponding to non-pixel regions of the substrateto be processed, respectively, the fixing apparatus further comprises:each of the second magnetic structures is configured to generate amagnetic field so that a mask plate used during the evaporation processand the magnetic field generator are approaching to each other under themagnetic field generated by the second magnetic structure.
 2. The fixingapparatus according to claim 1, wherein a thickness of each of theferromagnetic patterns is larger than or equal to 5 nm.
 3. The fixingapparatus according to claim 1, wherein each of the ferromagneticpatterns has a rectangle shape.
 4. The fixing apparatus according toclaim 1, wherein the ferromagnetic patterns are disposed in one-to-onecorrespondence with the pixel regions, and each of the ferromagneticpatterns is located at a center of a corresponding pixel region.
 5. Thefixing apparatus according to claim 1, wherein all the ferromagneticpatterns are electrically connected.
 6. The fixing apparatus accordingto claim 1, wherein a thickness of each of the ferromagnetic patterns islarger than or equal to 5 nm.
 7. The fixing apparatus according to claim1, wherein the ferromagnetic material is at least one selected from agroup consisted of Fe, Co and Ni.
 8. The fixing apparatus according toclaim 1, wherein the magnetic field generator is an electromagnet.